Method and system for charging a transport refrigeration system

ABSTRACT

A method for charging a phase change material (PCM) of a thermal accumulator provided in a refrigerated transport unit is provided. The refrigerated transport unit includes a prime mover to move the refrigerated transport unit, a transport refrigeration system (TRS) that includes a heat transfer fluid circuit. The heat transfer fluid circuit has a compressor, a heat exchanger, an expansion device and a PCM heat exchanger. The method requires monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit. Also, the method includes directing energy generated by the prime mover for moving the refrigerated transport unit to the TRS when the controller receives a braking signal from the braking sensor. Further, the method includes the TRS charging the PCM of the thermal accumulator via the heat transfer fluid circuit when the energy generated by the prime mover is directed to the TRS.

FIELD

Embodiments of this disclosure relate generally to a transport refrigeration system (TRS) including a thermal accumulator or thermal accumulator module having a phase change material (PCM). More specifically, the embodiments relate to a method and system for charging a PCM using braking energy from a vehicle.

BACKGROUND

A transport refrigeration system (TRS) is generally used to control an environmental condition such as, but not limited to, temperature and/or humidity of a transport unit. Examples of transport units include, but are not limited to, a container on a flat car, an intermodal container, a truck, a boxcar, or other similar transport unit (generally referred to as a “climate controlled transport unit”). A refrigerated transport unit is commonly used to transport perishable items such as, but not limited to, produce, frozen foods, and meat products. Generally, the refrigerated transport unit includes a transport refrigeration unit (TRU) that is attached to a transport unit to control the environmental condition of an interior space within the transport unit. The TRU can include, without limitation, a compressor, a condenser, an expansion valve, an evaporator, and fans or blowers to control the heat exchange between the air inside the interior space and the ambient air outside of the refrigerated transport unit.

SUMMARY

Embodiments of this disclosure relate generally to a transport refrigeration system (TRS) including a thermal accumulator or thermal accumulator module having a phase change material (PCM). More specifically, the embodiments relate to a method and system for charging a PCM using braking energy from a vehicle.

In some embodiments, the TRS can include a thermal accumulator compartment storing one or more thermal accumulators having a PCM. In some embodiments, the thermal accumulator compartment can include a thermal accumulator module having a PCM.

In some embodiments, the PCM is initially charged to a solid state and then is configured to gradually change phases into a liquid state while absorbing heat flowing through air surrounding the PCM and possibly heat produced by cargo.

The embodiments provided herein allow a TRS to use redundant braking energy from a prime mover that occurs during a braking condition to charge a PCM of a thermal accumulator and/or thermal accumulator module.

In some embodiments, the PCM is initially charged prior to a trip of a transport unit that includes the PCM for providing temperature control within a cargo space of the transport unit. Braking energy of a vehicle that includes and/or hauls the transport unit can then be used to charge the PCM so as to prolong the amount of time that the vehicle can remain in transport while maintaining temperature control within the cargo space and/or reduce a charging requirement of the PCM after the trip.

The embodiments provided herein can be used in a vehicle powered by a combustion engine, powered by an electric drive, and powered by a hybrid prime mover that includes a combustion engine and an electric drive that work together.

In one embodiment, a method for charging a PCM of a thermal accumulator provided in a refrigerated transport unit is provided. The refrigerated transport unit includes a prime mover to move the refrigerated transport unit, a TRS that includes a heat transfer fluid circuit. The heat transfer fluid circuit has a compressor, a heat exchanger, an expansion device and a PCM heat exchanger. The method requires monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit. Also, the method includes directing energy generated by the prime mover for moving the refrigerated transport unit to the TRS when the controller receives a braking signal from the braking sensor. Further, the method includes the TRS charging the PCM of the thermal accumulator via the heat transfer fluid circuit when the energy generated by the prime mover is directed to the TRS.

In another embodiment, a refrigerated transport unit is provided. The refrigerated transport unit includes a prime mover, a braking sensor, a controller, a transport unit and a TRS. The prime mover is configured to provide energy for moving the refrigerated transport unit. The braking sensor is configured to monitor a braking condition of the refrigerated transport unit. The controller is configured to monitor for the braking signal. The transport unit includes an interior space. The interior space includes a thermal accumulator module having a PCM and a PCM heat exchanger provided therein. The TRS includes a compressor. The PCM heat exchanger and the compressor form a heat transfer fluid circuit. When the controller receives a braking signal from the braking sensor, the prime mover is configured to direct energy to the TRS to charge the PCM.

In yet another embodiment, a method for charging a PCM of a thermal accumulator provided in a refrigerated transport unit is provided. The refrigerated transport unit includes a combustion engine to move the refrigerated transport unit and a TRS. The TRS includes a refrigeration circuit having a belt driven compressor, a condenser, an expansion device and a PCM evaporator. The method includes monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit. The method also includes directing mechanical energy generated by the combustion engine for moving the refrigerated transport unit to the belt driven compressor when the controller receives a braking signal from the braking sensor. Also, the method includes the TRS charging the PCM of the thermal accumulator via the refrigeration circuit when the mechanical energy generated by the prime mover is directed to the belt driven compressor.

In a further embodiment, a method for charging a PCM of a thermal accumulator provided in a refrigerated transport unit is provided. The refrigerated transport unit includes a combustion engine to move the refrigerated transport unit, a belt driven alternator configured to convert mechanical energy generated by the prime mover into electrical energy, and a TRS. The TRS includes a refrigeration circuit having an electric compressor, a condenser, an expansion device and a PCM evaporator. The method includes monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit. The method also includes the belt driven alternator converting mechanical energy generated by the combustion engine for moving the refrigerated transport unit into electrical energy when the controller receives a braking signal from the braking sensor. Also, the method includes directing the electrical energy to the electric compressor. Further, the method includes the TRS charging the PCM of the thermal accumulator via the refrigeration circuit when the electrical energy is directed to the electric compressor.

Also, in another embodiment, a method for charging a PCM of a thermal accumulator provided in a refrigerated transport unit is provided. The refrigerated transport unit includes both a combustion engine and an electric drive to move the refrigerated transport unit, and a TRS. The TRS includes a refrigeration circuit having an electric compressor, a condenser, an expansion device and a PCM evaporator. The method includes monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit. Also, the method includes the electric drive directing electrical energy for moving the refrigerated transport unit to the electric compressor when the controller receives a braking signal from the braking sensor. The method also includes the combustion engine directing mechanical energy generated for moving the refrigerated transport unit to an energy storage source when the controller does not receive a braking signal from the braking sensor. Further, the method includes the TRS charging the PCM of the thermal accumulator via the refrigeration circuit when the electrical energy is directed to the electric compressor.

In yet a further amendment a method for charging a PCM of a thermal accumulator provided in a refrigerated transport unit is provided. The refrigerated transport unit includes an electric drive to move the refrigerated transport unit, and a TRS. The TRS includes a refrigeration circuit having an electric compressor, a condenser, an expansion device and a PCM evaporator. The method includes monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit. Also, the method includes the electric drive directing electrical energy for moving the refrigerated transport unit to the electric compressor when the controller receives a braking signal from the braking sensor. The method also includes the TRS charging the PCM of the thermal accumulator via the refrigeration circuit when the electrical energy is directed to the electric compressor.

An advantage of the embodiments described herein is that an amount of time a TRS can use a PCM to provide an environmental condition within a refrigerated can be increased, as the PCM can be charged while the refrigerated transport unit is in transport. Also, as the embodiments described herein use redundant prime energy available during a braking condition energy savings for running a TRS can be achieved. Also, the embodiments described herein provide more efficient direct energy utilization of redundant energy generated by a prime mover.

Comments:

The following is noted with respect to the embodiments described herein.

The thermal accumulator discussed herein can include a PCM that is adaptable to heat or to cool a storage space (e.g., a cargo compartment) to a temperature suitable for the cargo stored in the storage space. The thermal accumulator can also be used for a defrost operation within the storage space.

Operation of the TRS for a refrigerated transport unit can be independent to various thermal loads that occur due to external conditions external the refrigerated transport unit. That is, the thermal accumulator of the TRS can maintain a desired temperature within the storage space of the refrigerated transport unit regardless of external conditions outside of the refrigerated transport unit.

The PCM used in the thermal accumulator can be any fluid which has a solid-liquid transition point in a rage between about −32° C. and about 0° C. The PCM can be compatible with metals, for example, aluminum. The PCM can store heat in a transition phase using a latent heat (e.g., heat of fusion). The PCM can store heat in a liquid phase. The PCM can have a phase transition temperature that absorbs changes in temperature of the refrigerated transport unit.

The thermal accumulator allows a transfer of heat from the PCM to an air space within the storage space and vice versa. The heat exchanger can include a single, dual, or multiple pass design. The thermal accumulator can use a natural or forced convection to facilitate heat exchange between the PCM and an air space within the storage space. In some embodiments, the thermal accumulator can include a wall or walls with a substantially flat surface and a wall or walls with at least a partially enhanced (e.g., ribbed surface). The thermal accumulator can store a PCM and/or include an empty or free expansion space within the thermal accumulator.

In some embodiments, a thermal accumulator compartment storing a thermal accumulator can be retrofitted into/onto a refrigerated transport unit. The thermal accumulator compartment can be installed to the refrigerated transport unit without specialized equipment. In some embodiments, the thermal accumulator compartment can be designed such that the weight of the thermal accumulator compartment can be supported by a floor, one or more side walls or a ceiling of the refrigerated transport unit. In some embodiments, the PCM can be provided in the thermal accumulator from the top.

The TRS can provide a defrost operation. In some embodiments, a second fluid or refrigerant may be used to perform a defrost operation. In some embodiments, the TRS can include an optional defrost device (e.g., heating bar(s), heating sheet(s), heating tube(s), etc.) for performing the defrost operation. In some embodiments, the thermal accumulator can include a second fluid or refrigerant line to perform the defrost operation. In some embodiments, the defrost operation can be performed in less than 24 hours.

In some embodiments, the TRS can include one or more fans. The power of the fans can be adjusted based on a temperature within the storage space. The fans can provide an air flow rate sufficient to reach a desired amount of heat transfer from the PCM in the thermal accumulator to an air space within the storage space and vice versa. The fans can be controlled/adjusted based on a desired set point temperature within the storage space.

BRIEF DESCRIPTION OF THE DRAWINGS

References are made to the accompanying drawings that form a part of this disclosure and which illustrate the embodiments in which the systems and methods described in this Specification can be practiced.

FIG. 1 illustrates a refrigerated transport unit, according to one embodiment.

FIG. 2 illustrates a flowchart of a method for charging a PCM of the thermal accumulator using energy generated from the prime mover during a braking condition, according to one embodiment.

FIG. 3 illustrates a flowchart of a method for charging a PCM of the thermal accumulator using energy generated from the prime mover during a braking condition, according to another embodiment.

FIG. 4 illustrates a flowchart of a method for charging a PCM of the thermal accumulator using energy generated from the prime mover during a braking condition, according to yet another embodiment.

FIG. 5 illustrates a flowchart of a method for charging a PCM of the thermal accumulator using energy generated from the prime mover during a braking condition, according to an additional embodiment

Like reference numbers represent like parts throughout.

DETAILED DESCRIPTION

Embodiments of this disclosure relate generally to a transport refrigeration system (TRS) including a thermal accumulator or thermal accumulator module having a phase change material (PCM). More specifically, the embodiments relate to a method and system for charging a PCM using braking energy from a vehicle.

That is, the embodiments described herein provide a TRS that is capable of directly converting braking energy of a vehicle into thermal energy that can be used to charge a PCM of a thermal accumulator or thermal accumulator module.

A suitable thermal accumulator or thermal accumulator module is described in U.S. Provisional patent application Ser. No. 14/268,239 (Attorney Docket 20420.0140US01), filed on May 2, 2014, and titled “Thermal Accumulator for a Transport Refrigeration System,” which is incorporated herein by reference in its entirety.

A “transport refrigeration system” (TRS) is generally used to control an environmental condition such as, but not limited to, temperature, humidity, and air quality within an interior space (e.g., cargo compartment) of a transport unit. Examples of transport units include, but are not limited to, a container on a flat car, an intermodal container, a truck, a boxcar, or other similar transport unit (generally referred to as a “transport unit”). Embodiments of this disclosure may be used in any suitable transport unit such as those listed above.

The TRS includes, for example, a heat transfer fluid circuit (e.g., a refrigeration circuit) for controlling the refrigeration of the interior space of a climate controlled transport unit. In one embodiment, the TRS can include one or more thermal accumulators and/or thermal accumulator modules. Embodiments described herein include thermal accumulators and thermal accumulator modules having a phase change material (PCM) contained therein. The PCM is configured in a first state, to absorb thermal energy from the interior space of the transport unit during transformation to a second state. The thermal accumulators and thermal accumulator modules can be replaceable and rechargeable outside of the climate controlled transport unit. In some embodiments, the TRS can include a PCM heat exchanger, at least a portion of which is disposed within the thermal accumulator and is configured to be in thermal communication with the PCM. The TRS can also include an expansion device, a compressor and one or more heat exchanger(s). The heat transfer fluid circuit connects the TRU and the PCM heat exchanger, and is configured to direct a heat transfer fluid (e.g., refrigerant) from the TRU to the PCM heat exchanger via the expansion device for charging the PCM.

In some configurations, the TRS can also include a transport refrigeration unit (TRU) (e.g., a TRU having a compressor, a heat exchanger, an expansion valve and optionally an evaporator all connected via a heat transfer fluid circuit). In configurations where the TRS includes the TRU, the thermal accumulator and/or thermal accumulator module may allow the TRU to be disabled for a period of time while still maintaining the desired environmental condition. Also, in some embodiments, PCM heat exchanger (e.g., an evaporator) can be disposed within a thermal accumulator or thermal accumulator module so as to be in thermal communication with the PCM. The PCM heat exchanger would be connected to the compressor, the heat exchanger and the expansion valve via the heat transfer fluid circuit (e.g., a refrigeration circuit). When the compressor is in operation, the PCM heat exchanger would be able to charge the PCM in the thermal accumulator or thermal accumulator module.

A “refrigerated transport unit” includes, for example, a transport unit having a TRS. A refrigerated transport unit can be used to transport perishable items such as, but not limited to, produce, frozen foods, and meat products.

A “phase change material” (PCM) includes, for example, a material that can store or release a large amount of energy upon a phase change (e.g., from a solid to a liquid, a liquid to a solid, etc.) while remaining at about a constant temperature. A PCM can gradually absorb heat (e.g., from an interior space of a climate controlled transport unit, etc.) while remaining at about a constant temperature during a phase transformation from a solid state into a liquid state. A PCM can, for example, be used to maintain an interior space of a climate controlled transport unit at a desired temperature.

A “eutectic PCM” includes, for example, a PCM that solidifies at a lower temperature than any other compositions made of the same ingredients.

An “aluminum compatible PCM” includes, for example, a PCM that is not corrosive to aluminum. Examples of aluminum compatible PCMs include, but are not limited to, a mixture of hydrogen peroxide and water, a propylene glycol and water mixture, and the like. An example of a PCM that is not aluminum compatible includes, but is not limited to, a PCM solution including salt (e.g., because the salt can be corrosive to aluminum).

The term “braking energy” as defined herein refers to energy generated by a prime mover of a vehicle during a braking condition.

A “braking condition” can be, for example, when the operator is braking, the refrigerated transport unit 100 moving downhill, etc.

The phrase “charging the PCM” as defined herein refers to restoring the PCM from the second state back to the first state so as to allow the PCM to provide an environmental condition within the interior space of the transport unit.

FIG. 1 illustrates one embodiment of a refrigerated transport unit 100 that includes a transport unit 105 and a TRS 110. The transport unit 105 is in the form of a straight truck that includes a cab 115 and an interior space 120. The cab 115 houses a prime mover portion 125, an optional electrical generator portion 130, a vehicle control portion 135, an energy storage source 140, a brake sensor 190 and an optional secondary energy storage device 145.

It is appreciated that in other embodiments, the transport unit can be, for example, a truck or trailer unit that can be attached to a tractor, a ship board container, an air cargo container or cabin, an over the road truck cabin, etc.

The prime mover portion 125 is configured to provide power to move the refrigerated transport unit 100 and to operate the TRS 110. The prime mover portion 125 can also be configured to charge the energy storage source 140 and the optional secondary energy storage device 145 and power the vehicle control portion 135.

In some embodiments, the prime mover portion 125 can be a combustion engine (e.g., diesel engine) (not shown) that generates mechanical energy to move the refrigerated transport unit 100. In other embodiments, the prime mover portion 125 can be an electric drive (e.g., motor-generator) (not shown) that generates electrical energy to move the refrigerated transport unit 100. In yet some other embodiments, the prime mover portion 125 can include both a combustion engine and an electric drive that uses both mechanical energy and electrical energy to move the refrigerated transport unit 100.

The optional electrical generator portion 130 is configured to convert energy from the prime mover 125 into another form of energy. In some embodiments, the optional electrical generator portion 130 can be a belt driven alternator that is connected to the combustion engine via a clutch mechanism (not shown) and can be configured to convert mechanical energy from the combustion engine into direct current (DC) electrical energy or alternating current (AC) electrical energy.

For example, when the prime mover portion 125 includes a combustion engine, the optional electrical generator portion 130 can be connected to the combustion engine and can be configured to convert mechanical energy generated by the combustion engine into electrical energy. The electrical energy can then be used to, for example, operate the TRS 110, power the vehicle control portion 135, charge the energy storage source 140, and charge the optional secondary energy storage device 145.

When the prime mover portion 125 includes an electric drive, the optional electrical generator portion 130 can be an inverter generator that is connected to the electric drive and is configured to convert DC electrical energy generated by the electric drive into AC electrical energy or vice versa.

In embodiments where the prime mover portion 125 includes both a combustion engine and an electric drive, the optional electrical generator portion 130 can include both a belt driven alternator and an inverter generator.

The vehicle control portion 135 can include a processor (not shown), a memory (not shown), a clock (not shown), and an input/output (I/O) interface (not shown). The vehicle control portion 135 is configured to monitor and control operation of the prime mover 125, the energy storage source 140, the brake sensor 190, the optional electrical generator portion 130 and the optional secondary energy storage device 145. The vehicle control portion 135 is also configured to communicate with a TRS controller 195.

The energy storage source 140 can be a vehicle supply system that is configured to store electrical energy and can provide the stored electrical energy to, for example, the prime mover 130 (when, for example, the prime mover 130 is a motor-generator), the vehicle control portion 135, the optional secondary energy storage device 145, components within the TRS 110, etc. The energy storage source 140 can be, for example, one or more batteries, super capacitors, etc.

The optional secondary energy storage device 145 can be, for example, an auxiliary power unit (APU) configured to provide heating, ventilation and air conditioning within the cab 115 when the prime mover 125 is disengaged and not in operation (e.g., during a driver rest period).

The brake sensor 190 is configured to determine when a braking condition occurs and send a braking signal to, for example, the vehicle control portion 135 and the TRS controller 195. A braking condition can be, for example, when the operator is braking, the refrigerated transport unit 100 moving downhill, etc.

The TRS 110 includes a TRU 150 that controls an environmental condition within the interior space 120. The TRU 110 is disposed on a front wall 155 of the transport unit 105. The TRU 110 includes a compressor 160, a heat exchanger 165 (e.g., condenser) with one or more heat exchanger fans 167 (e.g., condenser fans), an expansion valve 170 and a TRS controller 195.

The interior space 120 is configured to carry a cargo therein at a controlled environmental condition (e.g., temperature, humidity, air quality, etc.) via the TRS 110. In some embodiments, the interior space 120 can be divided into a plurality of zones, with each zone configured to operate at a separate environmental condition. The interior space 120 includes a thermal accumulator module 175 having a PCM (not shown). A PCM heat exchanger 180 (e.g., evaporator) is provided within the thermal accumulator 175 so as to be in thermal communication with the PCM.

The compressor 160, the heat exchanger 165, the expansion valve 170 and the PCM heat exchanger 180 are fluidly connected to form a heat transfer fluid circuit 185 (e.g., a refrigeration circuit). Accordingly, when the compressor 160 is in operation, the PCM heat exchanger 180 would be able to charge the PCM in the thermal accumulator module 175.

In some embodiments, the TRS 100 may also include a second evaporator and/or a separate evaporator unit that is part of the heat transfer fluid circuit 185 and can be configured to obtain a desired environmental condition (e.g., temperature, humidity, air quality, etc.) within the interior space 120, as is generally understood in the art.

The TRS controller 195 can include a processor (not shown), a memory (not shown), a clock (not shown), and an input/output (I/O) interface (not shown). Generally, the TRS Controller 195 is configured to control a refrigeration cycle of the TRS 100. In one example, the TRS Controller 195 controls the refrigeration cycle of the TRS 100 to charge PCM of the thermal accumulator module 175. In some embodiments, the TRS controller 195 can also be configured to obtain a braking signal from the braking sensor 190 and operate the TRS 100 based on the braking signal.

In one configuration, the compressor 160 can be a belt driven compressor, the prime mover 125 can be a combustion engine, and the compressor 160 can be connected to the prime mover 125 via a clutch (not shown). A controller (e.g., the vehicle control portion 135, the TRS controller 195) can be configured to instruct the clutch to connect the compressor 160 to the prime mover 125. Accordingly, mechanical energy generated by the prime mover 125 can be provided directly to the compressor 160 in order to drive the compressor 160 and thereby operate the heat transfer fluid circuit 185. Also, the optional electrical generator portion 130 can be a belt driven alternator that allows a portion of the mechanical energy generated by the prime mover 125 to be converted into electrical energy that can then be used to, for example, power the vehicle controller portion 135, charge the energy storage source 140 and the optional secondary energy storage device 145. FIG. 2 below illustrates one embodiment of a method for charging a PCM of the thermal accumulator 175 using energy generated from the prime mover 125 during a braking condition, according to this configuration.

In another configuration, the TRS 110 can be an electric TRS in which the compressor 160 is an electric compressor, the prime mover 125 can be a combustion engine, and the compressor 160 can be connected to the prime mover 125 via the optional electrical generator portion 130. The optional electrical generator portion 130 can include a belt driven alternator and can be connected to the prime mover 125 via a clutch (not shown). Accordingly, mechanical energy generated by the prime mover 125 can be converted into electrical energy by the optional electrical generator portion 130 and then directed to the compressor 160 in order to drive the compressor 160 and thereby operate the heat transfer fluid circuit 185. Also, a portion of the electrical energy converted by the optional electrical generator portion 130 can be used to, for example, power the vehicle controller portion 135, charge the energy storage source 140 and the optional secondary energy storage device 145. FIG. 3 below illustrates one embodiment of a method for charging a PCM of the thermal accumulator 175 using energy generated from the prime mover 125 during a braking condition, according to this configuration.

In yet another configuration, the prime mover 125 can be a hybrid prime mover that includes both a combustion engine and an electric drive. In this configuration, the TRS 110 can be an electric TRS in which the compressor 160 is an electric compressor. The compressor 160 can be connected to the electric drive of the prime mover 125 such that electrical energy generated by the electric drive can be used to drive the compressor 160 and thereby operate the heat transfer fluid circuit 185. Also, a portion of the electrical energy generated by the electric drive of the prime mover 125 can be used to, for example, power the vehicle controller portion 135, charge the energy storage source 140 and the optional secondary energy storage device 145.

In this configuration, the optional electrical generator portion 130 can include a belt driven alternator connected to the combustion engine of the prime mover 125 and configured to convert mechanical energy generated by the combustion engine into electrical energy. The electrical energy can then be used to, for example, power the vehicle controller portion 135, charge the energy storage source 140 and the optional secondary energy storage device 145.

In some embodiments of this configuration, the optional electrical generator portion 130 can also include an inverter generator that is connected to the electric drive of the prime mover 125 and can be configured to convert AC electrical energy generated by the electric drive into DC electrical energy. Accordingly, the inverter generator can provide DC electrical energy to, for example, drive the compressor 160, power the vehicle controller portion 135, charge the energy storage source 140 and the optional secondary energy storage device 145.

FIG. 4 below illustrates one embodiment of a method for charging a PCM of the thermal accumulator 175 using energy generated from the prime mover 125 during a braking condition, according to this configuration.

In one more configuration, the prime mover 125 can be an electric drive. In this configuration, the TRS 110 can be an electric TRS in which the compressor 160 is an electric compressor. The compressor 160 can be connected to the electric drive of the prime mover 125 such that electrical energy generated by the electric drive can be used to drive the compressor 160 and thereby operate the heat transfer fluid circuit 185. Also, a portion of the electrical energy generated by the electric drive of the prime mover 125 can be used to, for example, power the vehicle controller portion 135, charge the energy storage source 140 and the optional secondary energy storage device 145.

In some embodiments of this configuration, the optional electrical generator portion 130 can also include an inverter generator that is connected to the electric drive of the prime mover 125 and can be configured to convert AC electrical energy generated by the electric drive into DC electrical energy. Accordingly, the inverter generator can provide DC electrical energy to, for example, drive the compressor 160, power the vehicle controller portion 135, charge the energy storage source 140 and the optional secondary energy storage device 145.

FIG. 5 below illustrates one embodiment of a method for charging a PCM of the thermal accumulator 175 using energy generated from the prime mover 125 during a braking condition, according to this configuration.

FIG. 2 illustrates a flow chart of method 200 for charging a PCM of a thermal accumulator or thermal accumulator module (e.g., the thermal accumulator module 175) using braking energy from a vehicle (e.g., the cab 115), according to one embodiment. In this embodiment, the vehicle uses a combustion engine (e.g., diesel engine) as a prime mover (e.g., the prime mover 125) to operate the vehicle and to run a belt driven compressor (e.g., the compressor 160) of a TRS (e.g., the TRS 110).

At 205, a controller (e.g., the vehicle control portion 135, the TRS controller 195) monitors for a braking signal from a braking sensor (e.g., the braking sensor 190) indicating that the vehicle is operating under a braking condition (e.g., braking, downhill riding, etc.). At 210, the controller determines whether a braking signal is received. If a braking signal is received from the braking sensor, the method 200 proceeds to 215, 220 and 225. If a braking signal is not received from the braking sensor, the method 200 proceeds to 225.

At 215, the controller instructs a clutch to connect the belt driven compressor of the TRS to the combustion engine. At 220, the controller switches into operation one or more heat exchanger fans (e.g., the heat exchanger fans 167) of the TRS. Accordingly, mechanical energy generated by the combustion engine during the braking condition can be used to run a heat transfer fluid circuit (e.g., the heat transfer fluid circuit 185) of the TRS, thereby charging a PCM of a thermal accumulator or a thermal accumulator module in the transport unit. In some embodiments, the mechanical energy used to run the heat transfer fluid circuit is redundant energy not required to move the vehicle.

At 225, the controller connects the combustion engine to an alternator (e.g., the electrical generator portion 130) so as to convert the mechanical energy generated by the combustion engine into electrical energy. The electrical energy can then be stored, for example, in an energy storage source (e.g., the energy storage source 140), a secondary energy storage device (e.g., the secondary energy storage device 145), etc.

When the vehicle is operating under a braking condition, the ratio of mechanical energy generated by the combustion engine directed to run the belt driven compressor, the heat exchanger fans versus to run the alternator can vary. In one embodiment, the mechanical energy generated by the combustion engine can be directed first to the belt driven compressor until the PCM is, for example, fully charged before being directed to the alternator to charge, for example, the energy storage source, the secondary energy storage device, etc. In another embodiment, the mechanical energy generated by the combustion engine can be directed to the alternator until, for example, the energy storage source and the secondary energy storage device is, for example, fully charged before being directed to the belt driven compressor to charge the PCM. In yet another embodiment, the mechanical energy generated by the combustion engine can be directed to the alternator and the belt driven compressor concurrently so that, for example, the energy storage source, the secondary energy storage device and the PCM can both be charged at the same time.

FIG. 3 illustrates a flow chart of method 300 for charging a PCM of a thermal accumulator or thermal accumulator module (e.g., the thermal accumulator module 175) using braking energy from a vehicle (e.g., the cab 115), according to a second embodiment. In this embodiment, the vehicle uses a combustion engine (e.g., diesel engine) as a prime mover (e.g., the prime mover 125) to operate the vehicle and to run an electric compressor (e.g., the compressor 160) of an electric TRS (e.g., the TRS 110).

At 305, a controller (e.g., the vehicle control portion 135, the TRS controller 195) monitors for a braking signal from a braking sensor (e.g., the braking sensor 190) indicating that the vehicle is operating under a braking condition (e.g., braking, downhill riding, etc.). At 310, the controller determines whether a braking signal is received. If a braking signal is received from the braking sensor, the method 300 proceeds to 315 and the 320. If a braking signal is not received from the braking sensor, the method 300 proceeds to 320.

At 315, the controller instructs a clutch to connect a belt driven alternator (e.g., of the electrical generator portion 130) to the combustion engine so as to convert the mechanical energy generated by the combustion engine into electrical energy for use by the electric TRS. In particular, the controller uses the electrical energy to drive an electrically driven compressor and to switch on one or more heat exchanger fans (e.g., the heat exchanger fans 167) of the electric TRS. Accordingly, mechanical energy generated by the combustion engine during the braking condition can be used to run a heat transfer fluid circuit of the electric TRS, thereby charging a PCM of a thermal accumulator or a thermal accumulator module in a transport unit. In some embodiments, the mechanical energy converted by the belt driven alternator into electrical energy to run the heat transfer fluid circuit is redundant energy not required to move the vehicle.

At 320, the controller connects the combustion engine to a second alternator (e.g., of the electrical generator portion 130) so as to convert the mechanical energy generated by the combustion engine into electrical energy. The electrical energy can then be stored in an energy storage source (e.g., the energy storage source 140) and/or a secondary energy storage device (e.g., the secondary energy storage device 145).

When the vehicle is operating under a braking condition, the ratio of mechanical energy generated by the combustion engine directed to run the belt driven alternator versus to run the second alternator can vary. In one embodiment, the mechanical energy generated by the combustion engine can be directed first to the belt driven alternator until the PCM is, for example, fully charged before being directed to the second alternator to, for example, charge the energy storage source and/or the secondary energy storage device. In another embodiment, the mechanical energy generated by the combustion engine can be directed to the second alternator until, for example, the energy storage source and/or the secondary energy storage device is, for example, fully charged before being directed to the belt driven alternator to charge the PCM. In yet another embodiment, the mechanical energy generated by the combustion engine can be directed to the second alternator and the belt driven alternator concurrently so that the energy storage source, the secondary energy storage device and the PCM can all be charged at the same time.

When the vehicle is not operating under a braking condition, the mechanical energy generated by the combustion engine can be used to charge, for example, the energy storage source and/or the secondary energy storage device until the energy storage source and/or the secondary energy storage device is, for example, fully charged.

FIG. 4 illustrates a flow chart of method 400 for charging a PCM of a thermal accumulator or thermal accumulator module (e.g., the thermal accumulator module 175) using braking energy from a vehicle (e.g., the cab 115), according to a third embodiment. In this embodiment, the vehicle is a hybrid vehicle in which a prime mover (e.g., the prime mover 125) uses both a combustion engine (e.g., diesel engine) and an electric drive (e.g., motor-generator) to operate the vehicle and to run an electric TRS (e.g., the TRS 110). The electric drive can be powered by, for example, an energy storage source (e.g., the energy storage source 140).

At 405, a controller (e.g., the vehicle control portion 135, the TRS controller 195) monitors for a braking signal from a braking sensor (e.g., the braking sensor 190) indicating that the vehicle is operating under a braking condition (e.g., braking, downhill riding, etc.). At 410, the controller determines whether a braking signal is received. If a braking signal is received from the braking sensor, the electric drive is being used to operate the vehicle and the method 400 proceeds to 415 and 420. If a braking signal is not received from the braking sensor, the combustion engine and/or the electric drive is used to operate the vehicle based on operating parameters of the hybrid vehicle and the method 400 proceeds to 425.

At 415, the controller instructs the electric drive to provide electrical energy to the electric TRS. The electric TRS is configured to use the electrical energy generated by the electric drive to drive an electrically driven compressor (e.g., the compressor 160) and to switch on one or more heat exchanger fans (e.g., the heat exchanger fans 167) of the electric TRS. Accordingly, electrical energy generated by the electric drive during the braking condition can be used to run a heat transfer fluid circuit (e.g., the heat transfer fluid circuit 185) of the electric TRS, thereby charging the PCM of the thermal accumulator or thermal accumulator module in the transport unit. In some embodiments, the electrical energy directed to the electric TRS is redundant energy not required to move the vehicle. At 420, the controller instructs the electric drive to provide electrical energy to charge the energy storage source and/or a secondary energy storage device (e.g., the secondary energy storage device 145).

When the vehicle is operating under a braking condition, the ratio of electrical energy generated by the electric drive directed to run the electric TRS versus to charge the energy storage source and/or the secondary energy storage device can vary. In one embodiment, the electric drive can be configured to provide electrical energy to the electric TRS until the PCM is, for example, fully charged before providing electrical energy to charge the energy storage source and/or the secondary energy storage device. In another embodiment, the electric drive can be configured to charge the energy storage source and/or the secondary energy storage device is, for example, fully charged before providing electrical energy to the electric TRS until the PCM is, for example, fully charged. In yet another embodiment, the electric drive can be configured to charge the energy storage source and/or the secondary energy storage device concurrently with charging the PCM.

At 425, the controller directs a portion of mechanical energy generated by the combustion engine to run the vehicle to a belt driven alternator to convert the portion of mechanical energy into electrical energy. The electrical energy can then be used to charge the energy storage source and/or the secondary energy storage device.

In some embodiments, it is appreciated that the combustion engine and the electric drive are operating concurrently. Accordingly, for example, when the vehicle is not operating under a braking condition, the electric drive can use electrical energy stored in the energy storage source to provide energy to operate the vehicle concurrently with the combustion engine providing mechanical energy to operate the vehicle.

FIG. 5 illustrates a flow chart of method 500 for charging a PCM of a thermal accumulator or thermal accumulator module (e.g., the thermal accumulator module 175) using braking energy from a vehicle (e.g., the cab 115), according to a fourth embodiment. In this embodiment, the vehicle is an electric vehicle that uses an electric drive (e.g., motor-generator) as a prime mover (e.g., the prime mover 125) to operate the vehicle and to run an electric TRS (e.g., the TRS 110). The electric drive can be powered by, for example, an energy storage source (e.g., the energy storage source 140).

At 505, a controller (e.g., the vehicle control portion 135, the TRS controller 195) monitors for a braking signal from a braking sensor (e.g., the braking sensor 190) indicating that the vehicle is operating under a braking condition (e.g., braking, downhill riding, etc.). At 510, the controller determines whether a braking signal is received. If a braking signal is received from the braking sensor, the method 500 proceeds to 515 and 520. If a braking signal is not received from the braking sensor, the method 500 proceeds to 525.

At 515, the controller instructs the electric drive to provide electrical energy to the electric TRS. The electric TRS is configured to use the electrical energy generated by the electric drive to drive an electrically driven compressor (e.g., the compressor 160) and to switch on one or more heat exchanger fans (e.g., the heat exchanger fans 167) of the electric TRS. Accordingly, electrical energy generated by the electric drive during the braking condition can be used to run a heat transfer fluid circuit (e.g., the heat transfer fluid circuit 185) of the electric TRS, thereby charging the PCM of the thermal accumulator or the thermal accumulator module in the transport unit. In some embodiments, the electrical energy directed to the electric TRS is redundant energy not required to move the vehicle. At 520, the controller instructs the electric drive to provide electrical energy to charge the energy storage source and/or a secondary (e.g., the secondary energy storage device 145).

When the vehicle is operating under a braking condition, the ratio of electrical energy generated by the electric drive directed to run the electric TRS versus to charge the energy storage source and/or the secondary energy storage device can vary. In one embodiment, the electric drive can be configured to provide electrical energy to the electric TRS until the PCM is, for example, fully charged before providing electrical energy to charge the energy storage source and/or the secondary energy storage device. In another embodiment, the electric drive can be configured to charge the energy storage source and/or the secondary energy storage device until the energy storage source is, for example, fully charged before providing electrical energy to the electric TRS until the PCM is, for example, fully charged. In yet another embodiment, the electric drive can be configured to charge the energy storage source and/or the secondary energy storage device concurrently with charging the PCM.

At 525, the controller directs electrical energy stored in the energy storage source to the electric drive in order to operate the vehicle.

An advantage of the embodiments described above is that an amount of time a TRS can use a PCM to provide an environmental condition within a refrigerated can be increased, as the PCM can be charged while the refrigerated transport unit is in transport. Also, as the embodiments described herein use redundant prime energy available during a braking condition energy savings for running a TRS can be achieved. Also, the embodiments described herein provide more efficient direct energy utilization of redundant energy generated by a prime mover.

Aspects

It is noted that any of aspects 1-7, 8-18, 19, 20, 21 and 22 can be combined.

Aspect 1. A method for charging a phase change material (PCM) of a thermal accumulator provided in a refrigerated transport unit that includes a prime mover to move the refrigerated transport unit, a transport refrigeration system (TRS) that includes a heat transfer fluid circuit having a compressor, a heat exchanger, an expansion device and a PCM heat exchanger, the method comprising:

monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit;

directing energy generated by the prime mover for moving the refrigerated transport unit to the TRS when the controller receives a braking signal from the braking sensor; and

the TRS charging the PCM of the thermal accumulator via the heat transfer fluid circuit when the energy generated by the prime mover is directed to the TRS.

Aspect 2. The method according to aspect 1, further comprising:

preventing energy generated by the prime mover for moving the refrigerated transport unit from being directed to the TRS when the controller does not receive a braking signal from the braking sensor.

Aspect 3. The method according to any of aspects 1-2, wherein the TRS charging the PCM of the thermal accumulator via the heat transfer fluid circuit includes directing a heat transfer fluid through the PCM heat exchanger. Aspect 4. The method according to any of aspects 1-3, wherein the TRS charging the PCM of the thermal accumulator includes operating one or more heat exchanger fans of the TRS. Aspect 5. The method according to any of aspects 1-4, further comprising directing energy generated by the prime mover for moving the refrigerated transport unit to an energy storage source when the controller does not receive a braking signal from the braking sensor. Aspect 6. The method according to any of aspects 1-5, further comprising directing energy generated by the prime mover for moving the refrigerated transport unit to a secondary energy storage device when the controller does not receive a braking signal from the braking sensor. Aspect 7. The method according to any of aspects 1-6, further comprising when the controller receives a braking signal from the braking sensor, concurrently directing energy generated by the prime mover for moving the refrigerated transport unit to the TRS to charge the PCM and to an energy storage source to charge the energy storage source. Aspect 8. A refrigerated transport unit comprising:

a prime mover configured to provide energy for moving the refrigerated transport unit; a braking sensor configured to monitor a braking condition of the refrigerated transport unit;

the controller configured to monitor for the braking signal;

a transport unit including an interior space, the interior space including a thermal accumulator module having a phase change material (PCM) and a PCM heat exchanger provided therein; and

a transport refrigeration system (TRS) including a compressor;

wherein the PCM heat exchanger and the compressor form a heat transfer fluid circuit;

wherein when the controller receives a braking signal from the braking sensor, the prime mover is configured to direct energy to the TRS to charge the PCM.

Aspect 9. The refrigerated transport unit of aspect 8, wherein when the controller does not receive a braking signal from the braking sensor, the controller is configured to prevent the prime mover from directing energy to the TRS. Aspect 10. The refrigerated transport unit according to any of aspects 8-9, wherein when the controller receives the braking signal from the braking sensor, the prime mover is configured to direct energy to the TRS to operate the compressor and direct a heat transfer fluid through the PCM heat exchanger to charge the PCM. Aspect 11. The refrigerated transport unit according to any of aspects 8-10, wherein the TRS charging the PCM of the thermal accumulator includes operating one or more heat exchanger fans of the TRS. Aspect 12. The refrigerated transport unit according to any of aspects 8-11, further comprising:

an energy storage source connected to the prime mover, wherein the prime mover is configured to direct energy generated by the prime mover for moving the refrigerated transport unit to the energy storage source when the controller does not receive a braking signal from the braking sensor.

Aspect 13. The refrigerated transport unit according to any of aspects 8-12, further comprising:

a secondary energy storage device configured to store energy when the primary mover is disengaged, wherein the prime mover is configured to direct energy generated by the prime mover for moving the refrigerated transport unit to the secondary energy storage device when the controller does not receive a braking signal from the braking sensor.

Aspect 14. The refrigerated transport unit according to any of aspects 8-13, wherein when the controller receives a braking signal from the braking sensor, the prime mover is configured to concurrently direct energy to the TRS to charge the PCM and to an energy storage source to charge the energy storage source. Aspect 15. The refrigerated transport unit according to any of aspects 8-14, wherein the prime mover is a combustion engine. Aspect 16. The refrigerated transport unit according to aspect 15, wherein the compressor is a belt driven compressor. Aspect 17. The refrigerated transport unit according to any of aspects 8-14, wherein the prime mover is an electric drive and the compressor is an electrically powered compressor. Aspect 18. The refrigerated transport unit according to any of aspects 8-14, wherein the prime mover includes a combustion engine and an electric drive. Aspect 19. A method for charging a phase change material (PCM) of a thermal accumulator provided in a refrigerated transport unit that includes a combustion engine to move the refrigerated transport unit, and a transport refrigeration system (TRS) that includes a refrigeration circuit having a belt driven compressor, a condenser, an expansion device and a PCM evaporator, the method comprising:

monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit;

directing mechanical energy generated by the combustion engine for moving the refrigerated transport unit to the belt driven compressor when the controller receives a braking signal from the braking sensor; and

the TRS charging the PCM of the thermal accumulator via the refrigeration circuit when the mechanical energy generated by the prime mover is directed to the belt driven compressor.

Aspect 20. A method for charging a phase change material (PCM) of a thermal accumulator provided in a refrigerated transport unit that includes a combustion engine to move the refrigerated transport unit, a belt driven alternator configured to convert mechanical energy generated by the prime mover into electrical energy, and a transport refrigeration system (TRS) that includes a refrigeration circuit having an electric compressor, a condenser, an expansion device and a PCM evaporator, the method comprising:

monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit;

the belt driven alternator converting mechanical energy generated by the combustion engine for moving the refrigerated transport unit into electrical energy when the controller receives a braking signal from the braking sensor;

directing the electrical energy to the electric compressor; and the TRS charging the PCM of the thermal accumulator via the refrigeration circuit when the electrical energy is directed to the electric compressor.

Aspect 21. A method for charging a phase change material (PCM) of a thermal accumulator provided in a refrigerated transport unit that includes both a combustion engine and an electric drive to move the refrigerated transport unit, and a transport refrigeration system (TRS) that includes a refrigeration circuit having an electric compressor, a condenser, an expansion device and a PCM evaporator, the method comprising:

monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit;

the electric drive directing electrical energy for moving the refrigerated transport unit to the electric compressor when the controller receives a braking signal from the braking sensor;

the combustion engine directing mechanical energy generated for moving the refrigerated transport unit to an energy storage source when the controller does not receive a braking signal from the braking sensor; and

the TRS charging the PCM of the thermal accumulator via the refrigeration circuit when the electrical energy is directed to the electric compressor.

Aspect 22. A method for charging a phase change material (PCM) of a thermal accumulator provided in a refrigerated transport unit that includes an electric drive to move the refrigerated transport unit, and a a transport refrigeration system (TRS) that includes a refrigeration circuit having an electric compressor, a condenser, an expansion device and a PCM evaporator, the method comprising:

monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit;

the electric drive directing electrical energy for moving the refrigerated transport unit to the electric compressor when the controller receives a braking signal from the braking sensor; and

the TRS charging the PCM of the thermal accumulator via the refrigeration circuit when the electrical energy is directed to the electric compressor.

The terminology used in this Specification is intended to describe particular embodiments and is not intended to be limiting. The terms “a,” “an,” and “the” include the plural forms as well, unless clearly indicated otherwise. The terms “comprises” and/or “comprising,” when used in this Specification, specify the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components.

With regard to the preceding description, it is to be understood that changes may be made in detail, especially in matters of the construction materials employed and the shape, size, and arrangement of parts without departing from the scope of the present disclosure. The word “embodiment” as used within this Specification may, but does not necessarily, refer to the same embodiment. This Specification and the embodiments described are exemplary only. Other and further embodiments may be devised without departing from the basic scope thereof, with the true scope and spirit of the disclosure being indicated by the claims that follow. 

1. A method for charging a phase change material (PCM) of a thermal accumulator provided in a refrigerated transport unit that includes a prime mover to move the refrigerated transport unit, a transport refrigeration system (TRS) that includes a heat transfer fluid circuit having a compressor, a heat exchanger, an expansion device and a PCM heat exchanger, the method comprising: monitoring for, via a controller, a braking signal from a braking sensor of the refrigerated transport unit; directing energy generated by the prime mover for moving the refrigerated transport unit to the TRS when the controller receives a braking signal from the braking sensor; and the TRS charging the PCM of the thermal accumulator via the heat transfer fluid circuit when the energy generated by the prime mover is directed to the TRS.
 2. The method according to claim 1, further comprising: preventing energy generated by the prime mover for moving the refrigerated transport unit from being directed to the TRS when the controller does not receive a braking signal from the braking sensor.
 3. The method according to claim 1, wherein the TRS charging the PCM of the thermal accumulator via the heat transfer fluid circuit includes directing a heat transfer fluid through the PCM heat exchanger.
 4. The method according to claim 1, wherein the TRS charging the PCM of the thermal accumulator includes operating one or more heat exchanger fans of the TRS.
 5. The method according to claim 1, further comprising directing energy generated by the prime mover for moving the refrigerated transport unit to an energy storage source when the controller does not receive a braking signal from the braking sensor.
 6. The method according to claim 1, further comprising directing energy generated by the prime mover for moving the refrigerated transport unit to a secondary energy storage device when the controller does not receive a braking signal from the braking sensor.
 7. The method according to claim 5, further comprising when the controller receives a braking signal from the braking sensor, concurrently directing energy generated by the prime mover for moving the refrigerated transport unit to the TRS to charge the PCM and to an energy storage source to charge the energy storage source.
 8. A refrigerated transport unit comprising: a prime mover configured to provide energy for moving the refrigerated transport unit; a braking sensor configured to monitor a braking condition of the refrigerated transport unit; the controller configured to monitor for the braking signal; a transport unit including an interior space, the interior space including a thermal accumulator module having a phase change material (PCM) and a PCM heat exchanger provided therein; and a transport refrigeration system including a compressor; wherein the PCM heat exchanger and the compressor form a heat transfer fluid circuit; wherein when the controller receives a braking signal from the braking sensor, the prime mover is configured to direct energy to the TRS to charge the PCM.
 9. The refrigerated transport unit of claim 8, wherein when the controller does not receive a braking signal from the braking sensor, the controller is configured to prevent the prime mover from directing energy to the TRS.
 10. The refrigerated transport unit according to claim 8, wherein when the controller receives the braking signal from the braking sensor, the prime mover is configured to direct energy to the TRS to operate the compressor and direct a heat transfer fluid through the PCM heat exchanger to charge the PCM.
 11. The refrigerated transport unit according to claim 8, wherein the TRS charging the PCM of the thermal accumulator includes operating one or more heat exchanger fans of the TRS.
 12. The refrigerated transport unit according to claim 8, further comprising: an energy storage source connected to the prime mover, wherein the prime mover is configured to direct energy generated by the prime mover for moving the refrigerated transport unit to the energy storage source when the controller does not receive a braking signal from the braking sensor.
 13. The refrigerated transport unit according to claim 8, further comprising: a secondary energy storage device configured to store energy when the primary mover is disengaged, wherein the prime mover is configured to direct energy generated by the prime mover for moving the refrigerated transport unit to the secondary energy storage device when the controller does not receive a braking signal from the braking sensor.
 14. The refrigerated transport unit according to claim 12, wherein when the controller receives a braking signal from the braking sensor, the prime mover is configured to concurrently direct energy to the TRS to charge the PCM and to an energy storage source to charge the energy storage source.
 15. The refrigerated transport unit according to claim 8, wherein the prime mover is a combustion engine.
 16. The refrigerated transport unit according to claim 15, wherein the compressor is a belt driven compressor.
 17. The refrigerated transport unit according to claim 8, wherein the prime mover is an electric drive and the compressor is an electrically powered compressor.
 18. The refrigerated transport unit according to claim 8, wherein the prime mover includes a combustion engine and an electric drive. 